The invention relates to a solar cell comprised of a disc-shaped semiconductor body for exposure to rays on both sides and containing a pn-junction.
Solar cells suited for exposure to rays on both sides are, for example, known from German Offenlegungsschrift No. 1 614 832. The known solar cell comprises several pn-junctions on both surface sides of the semiconductor body. This solar cell must, therefore, be subjected to several diffusion processes, which renders it complicated and expensive to manufacture.
Also known are solar cells designed for single-sided exposure to rays which are provided with a grid- or finger-shaped conduction path system on the surface side for exposure to the incident light. The rear side of the semiconductor body is provided with a contact covering the entire surface. This solar cell for single-sided ray exposure is disadvantageous insofar as the rear side cannot be used for exposure to the incident light, and there is an increase in the operating temperature in the solar cell owing to the heat radiation to which it is subjected, which, in turn, decreases the efficiency of the solar cell. This is caused by the fact that the rear side contact of large surface area prevents the heat radiation from dissipating from the rear side of the cell again. Moreover, improvements made by a special surface treatment of the rear side of the cell are costly.